On a lazy August morning in a nonelection year, most House incumbents - 99 percent of whom get reelected - are enjoying vacation. But here he is, 446 days before the vote, shaking hands and showing off a local company's clean-diesel technology.

Welcome to one of the last competitive congressional districts left in America. Neither Republican red nor Democratic blue, this deep-purple swatch of southeastern Pennsylvania will host one of next year's hottest contests - and the politicking never ends.

"This district is in many ways a bellwether" for the 2006 mid-term election, says Amy Walter, who analyzes House races for the Cook Political Report, in Washington. Simply put, Republicans need to keep this seat; Democrats need to take it.

Not since Gettysburg has Pennsylvania been so crucial to the balance of power in a "house divided."

The Sixth Congressional District was carved with Gerlach, a former state senator, in mind. Its boundary lines, consequently, are as gerrymandered as a six-year-old's Etch-A-Sketch doodle. But that hasn't made things easy for him.

"I have to work a little harder [than my colleagues]," he says, noting that Al Gore and John Kerry beat President Bush here.

Interviews with voters along Route 30, which spans the district's southern edge, suggest Gerlach - and his fellow Republicans - may have to work even harder to win another term.

Concerns in Coatesville

Many East-coasters want to know when the real-estate bubble will pop. Folks in Coatesville, a steel-mill town 40 miles west of Philadelphia, want to know when it will float their way. A three-bedroom house here can be had for $57,000.

This is the Sixth's western fringe, too far to commute to Philly, too close to be Amish country. It's also one of the region's poorest areas, with sizable black and Latino communities, and residents have economic development on their minds.

Indeed, as private developers work to seize the town's historic buildings, the most politically charged two words in Coatesville aren't Iraq war, stem cells, or gay marriage, but eminent domain.

After a long discourse about the issue, John Ross and Jeff Deacon, who run The Religious Bookshoppe, explain their shifting views on national politics.

"I'm a lifelong Republican," says Mr. Ross, amid an art-deco interior where they hope to add a cafe. "But for the first time in my life, I can imagine voting Democrat." Mr. Deacon, too, has soured on Mr. Bush. Both cite frustration with the war in Iraq.

A similar refrain is heard just across the street, at Rusti's Beauty Supply. A bumper sticker on the window - "The Bush Promise: Survival of the Richest" - doesn't slow the flow of black women seeking hair-care products. Inside, owner Rusti Hoskins vents his views with more color than can be printed in a family newspaper. "I can't stand Bush," he says in gravelly tones. Once reliably Republican, Mr. Hoskins is now disgusted by the Iraq war.

His customers are more muted. Dovita Douglass, considering the candor of Rusti's politics as much as the subtlety of his beauty advice, is most concerned with finding a job. "I don't really think about Congress," she says.

Comments from those who do think about politics, however, could spell trouble for Republicans. To be sure, voters are hardly enamored with Democrats. But their feelings toward the president and his policies suggest a mood of dissatisfaction with Washington that could threaten Republican incumbents like Gerlach. It's a mood that buoys his Democratic challenger, Lois Murphy.

Misgivings in Main Line

"Voters here just aren't comfortable with the direction of the Republican Party," she says, citing its "reckless" record of fiscal management. Four young staffers are already hard at work for Ms. Murphy, a lawyer who, without much name recognition, lost to Gerlach by a mere 7,000 votes last year.

Murphy's campaign headquarters are in Narberth, one of the posh suburbs that stretch westward from Philadelphia along Pennsylvania's Main Line railroad. Route 30 is different in these leafy suburbs: A Maserati dealership and the manicured athletic fields of Villanova University make Coatesville seem a million miles away.

This area was once solidly Republican, but has been trending Democratic. Voters here are more politically oriented, but they're less willing to go on the record. In this Google age, many worry that colleagues will learn their partisan leanings.

Beverly Potter isn't one of them. How could Gerlach win her vote? "You'd have to pay me big money to vote Republican," jokes the self-described Roosevelt Democrat, outside the Bryn Mawr area bookstore she's run for 37 years.

Ted Butler, ambling through the upscale shops in Ardmore's outdoor Suburban Square Mall, is a Bush voter who is losing faith in his party. "I'm a little bit down on Congress," he says, adding that the US went into Iraq "for the wrong reasons" and that the war is "getting out of hand." Like others in this part of the district, Mr. Butler didn't know his representative.

Gerlach, for his part, rejects the notion of an anti-incumbent mood. He has welcomed fundraising support from Laura Bush and Karl Rove. The quality of his constituent service, he says, not national issues, is what will decide the election - in his favor.

The Bush administration, however, has eliminated any chance that Helene Speer might have voted for Gerlach. Nursing her son, Lemuel, she recounts grievances about national affairs. "Sometimes, I just think this is the worst time in the world," she concludes. "But then I remember what things were like when I was growing up in the 1970s, and that was worse," she recalls. "Things will get better again. I am hopeful."